TL;DR: even if your delete script confirms a full wipe and your Reddit profile page shows zero comment, there may still be comments left over (that you can find through a search engine and delete manually on Reddit)....
I saw your clarification that the comments persited on reddit.com. My thought was maybe the part of the DB which manages the comments of the posts was lacking behind.
But after weeks this should not be the case, so I take my comment back.
I just found out that not all of my Reddit comments had been deleted despite my profile page showing otherwise. ( kbin.social )
TL;DR: even if your delete script confirms a full wipe and your Reddit profile page shows zero comment, there may still be comments left over (that you can find through a search engine and delete manually on Reddit)....